Although music is dynamic and power will vary, anything close 1,500 watts RMS to each sub woofer would push it into its mechanical limit and eventually run the driver into failure. I know some drivers are conservatively rated, but a shallow mount that has an efficiency of 90db is not going to be 1,200 conservatively rated. I'd be very careful when adjusting the gains.

Well, having 1,500 watts on tap would actually be nice... this allows you to set your gains well below "normal" operation and therefor lower the noise floor (i.e. keeps white noise to a minimum). So your amp may have the capabilities to output 1,500 watts, but with a low gain setting it may only be pumping 400 watts.